The 23-year-old "We Found Love" singer's hair is not the only thing raising eyebrows as she was recently photographed smoking what appeared to be an illegal substance while on vacation in Hawaii, according to Mail Online.

The Bajan singer, whose birth name is Robyn Rihanna Fenty, took to Twitter shortly after the photographs were made public making unusual references to "kush," which is a common street name for cannabis, and some critics accused her of promoting drug use.

The incident is not the first time that Rihanna has been criticized for smoking in public, which many argue glamorizes the deadly habit.

In November the Ulster Cancer Foundation of Ireland labeled Rihanna "irresponsible" for endorsing the deadly habit, after she was spotted puffing on a cigarette while filming the music video for her hit song "We Found Love."

"Three-quarters of adult smokers start the habit as teenagers, which is why it is so irresponsible of Rihanna to influence her young fan base in this way," UCF Cancer Prevention Officer Doreen Reegan explained in a statement.

The singer, who continued her rise to fame following her 2009 assault from then-boyfriend Chris Brown, has attracted millions of fans worldwide since revealing her new "Good Girl Gone Bad" image, and is often criticized for her revealing stage costumes.

Rihanna is rumored to be among the list of artists who are scheduled to perform at the 2012 Grammy Awards.